TOWARDS A QUANTITATIVE PETROGRAPHIC DATABASE OF KHMER STONE MATERIALS—KOH KER STYLE SCULPTURE

A comprehensive quantitative petrographic database of sandstones used by the Khmers for sculptural purposes would be a helpful tool for archaeologists, museum curators and others interested in pursuing research on early stone usage, geological source and provenance. Towards that end, this paper presents quantitative petrographic analysis of stone materials used in the production of some free‐standing sculptures and architectural elements in the Koh Ker style of the 10th century from the collections of the National Museum of Cambodia and The Metropolitan Museum of Art. These materials are compared to samples from the quarry of Thmâ Anlong near the foothills of the Phnom Kulen, Sieam Reap province. Primary and secondary detrital modes and key grain‐size parameters are used to identify three sandstone types. The free‐standing sculptures are carved from feldspathic arenite and feldspato‐lithic to litho‐feldspathic arenite. Finely carved lintels are worked from a quartz arenite, which is significantly richer in quartz grains and of a finer grain size. The geological source of the two other lithotypes will have to await detailed geological survey of the Koh Ker area accompanied by petrographic study of selected samples from documented quarries. The significance and potentiality of quantitative petrographic study of Khmer stone materials are shown in supporting and integrating archaeological investigations in South‐East Asia.     

BLACK AND RED GRANITES IN THE EGYPTIAN ANTIQUITY MUSEUM OF TURIN: A MINERO‐PETROGRAPHIC AND PROVENANCE STUDY

A recent project to investigate the stone artefacts preserved in the Egyptian Antiquity Museum of Turin has been undertaken, with the aim of supplying their systematic classification and suggesting the provenance site of the original raw materials. This paper focuses on seven sculptures dating back to the New Kingdom (18th–19th Dynasties): the statue of Ramses II, three of the 21 sculptures of the goddess Sekhmet, the statue of the goddess Hathor, the Ram‐headed Sphinx and the sarcophagus lid of Nefertari. Petrographic observations have shown that all the sculptures are made of granitoid rocks, with variable composition from granite to granodiorite and tonalite. The observation of strong macroscopic analogies with the so‐called black and red granites outcropping in the Aswan area has suggested a common origin of all the raw materials used for their manufacture. In order to verify this provenance hypothesis, several samples were collected in the Aswan quarry districts. According to results of a minero‐petrographic and geochemical comparison between the statues and the Aswan quarry samples, it was possible to identify the source area of the stone sculptures and finally to highlight the importance of an archaeometric approach to the solution of archaeological problems.     

Monitoring façade soiling as a maintenance strategy for the sensitive built heritage

The color patterns generally found on the façades of architecturally sensitive buildings have an adverse impact on their aesthetics, to the detriment of their identity and potential economic value. A quantitative and qualitative study was conducted of the perception of aesthetic decay in the limestone on a heritage building. The study assessed building aesthetics between two façade cleaning operations, conducted in 1984–1986 and 2006–2008. Based on the calculation of the final or total soiling index, by means of in situ lightness measurement and three architectural design variables, the color distribution of the façades was quantified in 2006 and a model was developed to monitor façade soiling over time. The proposed model, a tool for planning preventive façade maintenance on architecturally sensitive buildings, advocates for sustainable cleaning operations. Its premise that periodic cleaning should only be conducted in areas where the limestone is affected by aesthetic decay redounds to minimised intervention and lower building management costs.     

The Feathered Serpent Pyramid at Teotihuacan: decay,conservation and future perspectives

Abstract

The Feathered Serpent Pyramid at Teotihuacan, Mexico, is one of the most outstanding monuments of Mexican archaeological heritage. However, the volcanic stones that constitute the main façade of this building are subject to complex deterioration phenomena that include decay caused by the presence of water and soluble salts, as well as inappropriate treatments carried out in past decades. Agents of decay are explained in the article, as well as the means of diagnosis employed for their study. Recent conservation activities and other potential conservation treatments are also discussed.     

Nahal Lavan 108: A Pre-Pottery Neolithic a Site in the Western Negev,Israel

Abstract

Although the recent publication of the results of excavation and restoration in the Siq at Petra by the Petra National Trust has thrown welcome light on the hydraulic engineering skills of the Nabataeans, it is suggested here that the conclusions reached by the authors regarding the chronology of those works are not necessarily correct and should not be accepted as definitive. It is shown that the interpretation of the ceramic evidence is faulty and that other, epigraphic, evidence is ignored. In particular, it is argued that the major works — the dam and the tunnel — as well as the paved road through the Siq, may be as late as, or even later than, the middle of the 1st century AD, rather than the late 1st century BC, as the authors assume. It is further suggested that this could also be the date of the Khazneh, and that this may be indicated also by the recent discovery of earlier tomb façades beneath the Khazneh.     

COMPOSITIONAL CHARACTERIZATION OF FRENCH LIMESTONE: A NEW TOOL FOR ART HISTORIANS*

Limestone from quarries known to medieval craftsmen and from the monuments they built and embellished, as well as from carvings now in museum collections, has been characterized by neutron activation analysis. Specimens from 38 quarries in the Lutetian and Jurassic limestone formations of France and from sculptures in American and French museums have been tested, and the results have been compiled in a data base to which art historians may refer when attempting to determine provenance for sculptures. Multivariate statistical analysis of concentration data shows stone from a particular quarry in the Paris basin to be compositionally homogeneous and distinguishable from other quarries in the same formation. The same approach to data related to quarries near the Burgundian abbey of Cluny finds general agreement between classifications based on compositional and on petrographic data, but the number of samples available for analysis at the time of writing was insufficient to achieve the finer distinctions reported for the Paris basin.     

‘China-ware in the skies’: overlapping identities in the ornamental use of plates in Uruguay

Abstract

This is the study of a church where tableware manufactured in Great Britain was used to decorate the façade in the early 19th century. An argument is made that this one surviving case points to a larger regional tradition, now lost, whose greatest exponent was Montevideo Cathedral, Uruguay. The hypothesis presented here is that the use of British plates in religious façades shortly before the South American Wars of Independence was part of a search for identity in a region trying to break away from Spain, and in the process of becoming a small republic between the two larger countries of Argentina and Brazil.     

COLD NEUTRON PROMPT GAMMA ACTIVATION ANALYSIS—A NON‐DESTRUCTIVE METHOD FOR CHARACTERIZATION OF HIGH SILICA CONTENT CHIPPED STONE TOOLS AND RAW MATERIALS*

Recently, several archaeometrical projects have been started on the prehistoric collection of the Hungarian National Museum. Among the analytical methods applied, non‐destructive prompt gamma activation analysis has a special importance. We have also tested the potential of this method on chipped stone tools, with the aim of determining their exact provenance. On the basis of major and trace element components, characterizations of stone tools and their raw materials—silicites (flint, chert, radiolarite and hornstone) as well as volcanites (felsitic porphyry and obsidian)—were performed. We discuss some important results concerning each group, as case studies. Compiling the data set of different PGAA analysis series, compositions of 110 samples are reported, including 76 archaeological pieces. In the future, we plan to extend the number of investigated objects in each class.     

INVESTIGATING MATERIAL DECAY OF HISTORIC BUILDINGS USING VISUAL ANALYTICS WITH MULTI‐TEMPORAL INFRARED THERMOGRAPHIC DATA

This paper shows how visual analytics methodology can be used to facilitate interpretation of multi‐temporal thermographic imagery for the purpose of restoration of cultural heritage. We explore thermographic data in a visual environment from the unifying spatio‐temporal perspective in an attempt to identify spatial and spatio‐temporal patterns that could provide information about the structure and the level of decay of the material, and the presence of other physical phenomena in the wall. The approach is tested on a thermographic dataset captured on the façade of a Romanesque building from the 13th century—the Cathedral in Matera (Italy).     

Historical materials from the post-Cistercian abbey in Kamieniec Ząbkowicki (southwestern Poland)—application of mineralogical methods for identification of source of raw materials

In this paper, we use a set of methods applied for geosciences to reveal the provenance of raw materials and historical aspects of technology of lime production from the post-Cistercian church (southwestern Poland). Two types of building stones (mica schists and sandstones) and two groups of mortars, related with two different construction phases (Gothic and Baroque), were used for construction of the church façade. Principal difference between binding materials involves the presence of Mg-rich phase within Baroque mortars as a result of carbonation of a dolomitic lime whereas Gothic mortars are devoid of hydromagnesite. Mineral composition of the fillers of both mortars is similar, suggesting the same origin represented by local eluvium. Binders of studied mortars are composed of calcite and/or hydromagnesite and rich in lime lumps suggesting incomplete calcination. Studied mortars are weathered which is manifested by presence of gypsum. However, there is no evidence of commonly occurring Mg-rich secondary phases within Baroque mortar probably due to higher solubility of these salts comparing to gypsum. Mineralogical study combined with archeological and geological information enables us to indicate potential sources for the studied building materials. Metamorphic rocks, prevailing within the façade, come from abandoned quarries located in the closest vicinity of the church, whereas sandstones were acquired from the deposits located at a distance of tens of kilometers from the Kamieniec Z?bkowicki. Raw materials used for lime burning were gathered from Przeworno (Gothic mortars) and Z?oty Stok area (Baroque mortars) located approximately 25–30 and 12 km from studied church.     

SPECTROSCOPIC INVESTIGATION OF RED STAINS AFFECTING THE CARRARA MARBLE FAÇADE OF THE CERTOSA OF PAVIA

The nature of the large red stains exhibited on the Carrara marble elements of the Certosa of Pavia façade was investigated by means of spectroscopic techniques and scanning electron microscopy. Although previous microbiological analysis has demonstrated the presence on the stone of a bacterial strain identified as Micrococcus roseus, that is capable of carotenoid production, it has been ascertained in the present study that an inorganic pigment, namely Pb₃O₄, is responsible for the observed coloration. On small green spots, the presence of photosynthetic micro-organisms has been demonstrated by microbiological analysis and confirmed by resonance Raman spectroscopy.     

LEAD ISOTOPE AND TRACE ELEMENT ANALYSIS IN THE STUDY OF OVER A HUNDRED SOUTH INDIAN METAL ICONS*

Technical investigations were made on 130 South Indian statuary images and a few miscellaneous artefacts mostly sampled from the Government Museum, Madras, India, and from the Victoria and Albert Museum and the British Museum, UK. Lead isotope investigations were attempted on 60 of these, and compositional analysis for 18 elements on 115, using inductively coupled plasma optical emission spectroscopy; thus, for 40 objects both lead isotope and trace element analysis was done. From the isotopic and elemental framework, insights are obtained into some art-historical problems of images and artefacts of the Pre-Pallava, Pallava, Chola (i.e., Vijayalaya Chola), Later Chola (i.e., Chalukya-Chola and Later Pandya), Vijayanagara (and Early Nayaka) and Later Nayaka (and Maratha) dynasties, spanning the Early Christian era to the nineteenth century, along with a few other regional styles. Inferences are also made regarding provenance of the lead and the early use of zinc and brass in the early historic period (c. fourth century BC—fourth century AD).     

Dynamic One-Sided Out-Of-Plane Behavior of Unreinforced-Masonry Wall Restrained by Elasto-Plastic Tie-Rods

Past earthquakes have shown the high vulnerability of existing masonry buildings, particularly to out-of-plane local collapse mechanisms. Such mechanisms can be prevented if façades are restrained by tie rods improving the connections to perpendiculars walls. Whereas in the past only static models have been proposed, herein the nonlinear equation of motion of a monolithic wall restrained by a tie rod is presented. The façade, resting on a foundation and adjacent to transverse walls, rotates only around one base pivot and has one degree of freedom. Its thickness is explicitly accounted for and the tie rod is modeled as a linear elastic—perfectly plastic spring, with limited displacement capacity. The model is used to investigate the response to variations of wall geometry (height/thickness ratio, thickness), tie rod features (vertical position, length, prestress level), and material characteristics (elastic modulus, ultimate elongation, yield strength) typical of historical iron. The most relevant parameter is the steel strength, whereas other characteristics play minor roles allowing to recommend reduced values for pre-tensioning forces. The force-based procedure customary in Italy for tie design is reasonably safe and involves protection also against collapse, although probably not enough as desirable.     

Plasters from Different Buildings of the Sacred Precinct of Tenochtitlan (Mexico City): Characterization And Provenance

In this work, we present the results of the characterization of 20 lime plaster samples taken from the Sacred Precinct of Tenochtitlan (Mexico City), the ancient capital of the Aztec empire. The samples come from different buildings of this precinct (A, B and D) and from the west façade of phase VI of the Templo Mayor pyramid. The objective of the work is to characterize the plaster samples, to understand the raw materials used, and to evaluate the presence of similarities and differences among the samples in the building techniques and raw materials employed. All the samples were studied with OM, SEM–EDS and LA–ICP–MS. The study provided evidence of the plastering and replastering practice in the same constructive phases. The results of the analyses showed the existence of important similarities and differences among buildings and constructive phases in the Sacred Precinct. In order to understand the provenance of the limestone used in the plasters, the lumps and the binder of the samples were analysed. The results were compared with those of the limestone outcrops located in central Mexico. The provenance study showed that all the limestone used in the construction of the analysed buildings of Tenochtitlan's Sacred Precinct comes from the Tula region.     

Some considerations for the reburial of painted lime stucco façdesin the Maya region

Abstract

The conservation of Maya stucco façadesin humid tropical conditions poses significant challenges. Professionals in the region consider that reburial is one of the most easily accomplished and cost-effective conservation options; and reburial of modelled and painted lime plaster façades, in conjunction with the construction of exposed replica façadesoverlying the reburied originals, has been or is being considered as a preservation strategy at a number of sites in the region. This is illustrated by two case studies from Belize and one from Guatemala. However, more research is needed to fully understand the benefits and risks of reburial, and to determine the optimal conditions and techniques specifically suitable for wet tropical climates. The range of issues that must be considered for reburial of stucco façadesin this region include their conservation needs in relation to the susceptibility of ancient materials to climatic conditions, management issues such as visitor and interpretation needs and the problem of looting in the region, the feasibility of solutions in relation to available resources, choice of methods and materials used in interventions, and the impact of reburial on the significance of a site, amongst others.     

Conservative Think Tanks and Public Politics

The privileged position occupied by think tanks in public debate is reflected in their access to mainstream media and their political commentary frequently accepted as independent expert opinion. However, behind the carefully constructed and closely guarded façade of intellectual autonomy is a network of interests drawn together in a campaign to reshape political values. By tracing the intellectual antecedents and the historical origins of think tanks and their role in fostering neoliberalism, we assess the emerging neoconservatism and the implications for public debate.     

A Bronze Age Quarry in Eastern Crete

Abstract

The sandstone quarry at Mochlos is one of four major quarries in eastern Crete that were worked during the New Palace Period of Minoan civilization (ca. 1700–1450 B.C.) to produce large ashlar blocks for nearby Minoan sites. At that time sandstone, or ammoudha, as it is known locally, was especially valued as a building material, partly because of its distinctive color and texture, but mainly because of the ease with which it could be cut, and the stone was used extensively for exterior façades, for walls around interior courts, and for other architectural features of the more important buildings on these sites. This article describes the quarry at Mochlos in some detail, including the quarrying techniques employed, and argues that the destination of the stone from the Mochlos quarry was the Minoan palace at Gournia. The article ends with a comparison of the four ammoudha quarries in eastern Crete.     

COUNTRY HOUSE POEMS: THE POLITICS OF A GENRE

Abstract

The St. Louis Art Museum’s statue of Reclining Pan proved inspirational to many artists of the seventeenth century, none more so than Giovanni Benedetto Castiglione. The artist reproduced the statue in many of his works, making it a symbol of his invenzione. Previously, the few reproductions known of the statue have given the impression that Baroque audiences considered it antiquwct 2 e, and of less interest than other antiquities. This article corrects that assumption by examining Castiglione’s, as well as Peter Paul Rubens’, Joachim von Sandrart’s, Nicolas Poussin’s, and Salvator Rosa’s uses of the statue. The artists used the Pan as both figural exemplar and symbol for pastoral themes. These artistic responses are here set alongside new information concerning the Pan’s seventeenth-century provenance, display, and attribution to Bernini, to reveal the Reclining Pan as a primary catalyst for the period’s extensive Arcadian and bacchanalian imagery while simultaneously representing lessons of the classical style.     

Modeling and deterioration mapping of façades in historical urban context by close-range ultra-lightweight UAVs photogrammetry

Deterioration mapping of façades may be a challenging task in historical urban contexts, often characterized by narrow streets and tall buildings. In these situations, the application of Terrestrial Laser Scanning or Terrestrial Photogrammetry does not provide satisfactory results. Furthermore, the use of Unmanned Aerial Vehicles, the so-called “drones”, is generally forbidden in crowded places for safety reasons unless they are lighter than a weight imposed by the regulations in force in each country. This article presents the application of a very small and ultra-lightweight drone (less than 300 g) equipped with a low-cost camera, particularly suitable for operating in very narrow spaces. A close range photogrammetric survey performed to analyze a huge historical building façade in Bologna (Italy) pointed out a good accuracy level, confirmed by the validation of the results carried out by a 3D laser scanner survey. Moreover, a map of the degradation has been realized to support further restoration analysis, demonstrating that this low-cost, fast, and easy-to-use survey technique can be applied to other similar urban contexts at the same time.     

The Use of a Large-Scale Seismic Vulnerability Assessment Approach for Masonry Façade Walls as an Effective Tool for Evaluating,Managing and Mitigating Seismic Risk in Historical Centers

ABSTRACT

The vulnerability assessment of the building stock in a given territorial area, such as a city or an entire country, is a key prerequisite for evaluating risk, not only because of the potential physical consequences resulting from the occurrence of an event, but also because it is one of the few aspects in which engineering research can intervene. In fact, the rigorous vulnerability assessment of existing buildings followed by the implementation of appropriate retrofitting solutions can help to substantially reduce the levels of physical damage and economic impact of future events. Particularly regarding the seismic vulnerability assessment of historical centers, the amount of knowledge that has been accumulated over the past decades, together with the broad damage data obtained from post-earthquake damage surveys, provides a singular opportunity to develop and calibrate innovative large-scale seismic vulnerability assessment approaches, which can be used to outline and support risk mitigation and management strategies. This article addresses this issue by discussing the use of a large-scale seismic vulnerability assessment methodology for masonry façade walls as a tool for evaluating the potential benefit resulting from the application of different seismic retrofitting strategies, both considering their contribution to reduce post-event urban losses and accessibility.